Improvement in bolts



W. E. MBLLER.

Blts.

Patented 0130.31, 1872.

INvENTmR- WITNEEEEE.

WILLIAM It. MILLER, OF BALTIMORE, MARYLAND.

EMPRQVENENT IN GL'TS.

Specification forming part of Letters Patent No. Egh, dated December 31,1872.

To all whom it may concern:

Be it known that I, WILLIAM R. MILLER, of

the city of Baltimore, county of Balitmore and a small or auxiliarybolt, so that the latter may act automatically as a lock and prevent themain bolt from being moved back after 'the door has been bolted. Mysmall bolt is provided with a groove, in which a feather or projectiontits, so as to keep the bolt always in a perpendicular position, and toprevent it from being withdrawn and lost.

In the accompanying drawing, Figure l represents a side elevation of myinvention, showing the bolt thrown back; Fig. 2 is a similar view,showing the bolt locked; and Fig. 3 is a section of the locking-bolt,showing the groove and feather.

ab represent an ordinary door-bolt, the plate b being provided with thestop c to limit the back movement of the bolt. Secured to the plate nearits rear end is a small bolt, d, placed at right angles to the main onea, and which, while thebolt is drawn back, rests upon its top, as shownin Fig. l, but which, as soon as the bolt is shot forward, falls behindits rear end, as shown in Fig. 2, from its own gravity, and forms asecure and effective lock.

In order to keep this small bolt always in a perpendicular position, soas to insure its falling as soon as the large bolt is shot forward, andalso to prevent its being withdrawn accidentally, I iorm a feather orprojection, t', upon the plate b, which tits in a longitudinal groovecutin the bolt, as shown in Fig. 3.

This device is cheap, simple, and effective, and prevents the bolt frombeing shoved back from the outside.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

The grooved locking-bolt d, having feather or projection i, incombination with the main bolt a, and arranged to drop automatically inthe rear of the same, thereby locking it, substantially as shown anddescribed, for the purpose set forth.

In testimony that I claim the foregoing as my invention I hereunto affixmy signature this 5th day of December, 1872.

WM. It. MILLER.

Witnesses:

W. K. DUHAMEL, ALEX. S. DAvrnsoN.

